Our modern environment can impact on breathing problems.

Sometimes we hear of yards or stables that have had a ‘virus’ or ‘viral problems’ for years! This of course is a ridiculous notion. More often other ‘ environmental’ factors or ‘pathogens’ are the root cause of these longer term problems.

Any increase in the incidence or severity of lower airways ( lung) inflammation, hypersensitivity or disease will invariably be accompanied by an increase in the reported incidence of ‘breathing problems’. The reason for this is simple. If the lungs are not functioning maximally then more air must be provided to the lungs to compensate for this loss of function. This means upper airways are more likely to be overloaded, increasing the likelihood of airways collapse particularly during periods of maximum demand. Often the last 3 to 4 furlongs of a race.


Specific bacterial and occasionally fungal infections can be responsible for increases in lower airways dysfunction. However lower airways can also be affected by other ‘environmental irritants’ . The relative impact of these irritants on the airways will be directly related to 3 contributing factors.

(i) The general state of health of the airways at the time of exposure.  If already inflamed the impact is greater.

(ii) The concentration of irritant  and the frequency of exposure.

(iii) The stage of training when exposure occurs. A resting horses airways are quite resilient whilst a horse in heavy training can have airways as sensitive as those of a canary.


- Potential irritant checklist -

1) Pollens from cash crops- the most notorious of which is Rape Seed pollen. These are of course seasonal and are delivered to the airways via prevailing winds. 

2) Dust mites and other stable bugs. Always present and thus concentrations important. Regular bedding changes will usually keep levels at a minimum.

4) Bedding / hay - Hay dust is a well recognised irritant.  Soaking hay or feeding outside the stall  in a small open yard can reduce inhalation rates. Paper, cardboard and wood shavings appear to be less reactive when used as bedding.

5) Arena /  menage base - any surface in constant use can interplay with airway surfaces as its components are kicked into the air during exercise. The size of particles and the nature of the compound is important. Sand / dust is less likely to irritate significantly . Synthetic surfaces are often quite inert when initially laid due to their relatively large particle size. However with constant use the particulate size of some components can be reduced. These particles are then more likely to become airborne and come into contact with respiratory mucosas. See manufactures recommendations for the use by date and then replace. This date will of course be relative to usage. This factor is more significant in an indoor arena or any environment where ventilation is poor.

6) Factories / industry. There have been cases where the performance of hundreds of racing horses has been adversely affected by factory emissions. If fall out from factories is occurring ( you can often smell these) contact the factory and environmental authorities and request that a monitoring device be set up at your yard / stables.

7) Agricultural sprays ( herbicides and pesticides) . Exposure is usually accidental and results from spray drift. Discuss spraying protocols with farmer / neighbour. Establish buffer zones which need to take into account prevailing winds. Make sure you are notified prior to spraying so that barns can be closed or animals removed from barns and gallops. These sprays were not developed for use on animals ( including the human animal).

N.B.  some of these agents are also absorbed through the skin.

8) Smoke from fires .  What are you burning ? Smoke including that which is produced when burning organic matter is an airways irritant in itself.  Plastic and other synthetic substances can produce very toxic smoke. Those plastic covers from shavings bales, etc.

9) National pollution - Likely to be relevant only in very heavily built up areas. See national pollution levels.


Originally published in Pacemaker UK